Building a S̶t̶r̶o̶n̶g̶ ̶3̶5̶0̶ 383 for Frank the Tank…

I have been punching numbers into a few online calculators to figure out how compression ratio works... Which if I'm correct, is important to where I start to put together my parts list, yes? I think I'm starting to make some sense of it..

In Australia we can get 98-octane pump fuel. What is the optimum static compression ratio that I would chasing to run on 98?
 
I truly believe this is one of the best CR calculator anywhere, you can compare 5 engines side-by-side. Can't do that with any online calculators. It has both static and dynamic CR and cranking pressures. Be sure and read the notes of each row, some rows don't have much effect and can be left as is if you don't have the info.

Download the file called "DynamicCompressionRatioCalculatorWithCrankingPressure03.xlsx". It's at the bottom of the first post.

http://garage.grumpysperformance.co...comp-ratio-cranking-pressure-calculator.4458/
 
JimmyDuncan said:
Sounds like there's going to be many trips to the machine shop... :) I better choose one that isn't too much of a hike..

So, once I have the block initially checked and bored and decked, how do I figure out ahead of time all the required measurements for all the parts to be purchased? I'm aware that the bore diameter, deck height, gasket height, head chamber size and piston top type all go into the CR of the engine, but can that all be figured out now? Is there a calculator or a step by step way to do the math now (or once the block is bored) to confirm the parts list? Because it sounds like it will be a "if that then this", situation... and I will need to have the parts list all laid out before choosing the rotating assembly, which will include the pistons? If you have any links to info on how it all comes together, I'll happily read them :)
Click to expand...

You have to work the DCR and the piston tops together along with the heads and camshaft you want to buy. They work as a unit to determine DCR. DCR is probably more important that SCR.

Are you familar with Dynamic Compression Ratio (DCR)?

Notice how I played with the piston top(Dome Config) and the Intake Valve Closing (IVC) angle to keep the DCR below 8.25. That's about the highest we can go with our gasoline here. The link to the ProMaxx heads show a 64 cc chamber, but most heads come in two sizes. Most likely it's also available in something like 70 cc, another possible combination. It's like solving for simultaneous equations.

Are you buying a completely new rotating assembly or working with what you already have??? Has that decision been made???

DCR_CalculationExample.JPG

The machine shop does take several trips. The Excel spreadsheet link below can help with that. Do you have Excel or Open Office???

http://garage.grumpysperformance.co...et-for-tracking-your-machine-shop-costs.3423/
 
JimmyDuncan said:
In Australia we can get 98-octane pump fuel. What is the optimum static compression ratio that I would chasing to run on 98?
Click to expand...

I suspect Australia uses the RON rating and the US uses R+M/2 rating, which is lower that RON. Maybe Grumpy will have an idea how the two ratings compare.
 
I recall Australia and European 98 is much lower when Motor Octane converted. At Best 89-91 motor octane.

Some of the most important links to find and save Rick from the old site is the Dynamic compression ratio to Fuel octane levels
And Static compression to Engine Thermal efficiency charts
 
No one is running 110 motor octane Race Gas but me this year.
 
Indycars said:
You have to work the DCR and the piston tops together along with the heads and camshaft you want to buy. They work as a unit to determine DCR. DCR is probably more important that SCR.

Are you familar with Dynamic Compression Ratio (DCR)?

Notice how I played with the piston top(Dome Config) and the Intake Valve Closing (IVC) angle to keep the DCR below 8.25. That's about the highest we can go with our gasoline here. The link to the ProMaxx heads show a 64 cc chamber, but most heads come in two sizes. Most likely it's also available in something like 70 cc, another possible combination. It's like solving for simultaneous equations.

Are you buying a completely new rotating assembly or working with what you already have??? Has that decision been made???

View attachment 5720

The machine shop does take several trips. The Excel spreadsheet link below can help with that. Do you have Excel or Open Office???

http://garage.grumpysperformance.co...et-for-tracking-your-machine-shop-costs.3423/
Click to expand...

Ok thanks. That makes sense.

I'm aware of the DCR, but not sure what number I'm chasing... I'll look into it some more.

Yes, I played around with the numbers myself (thanks again for the calculator), and it made sense what was going on.

I'm going to buy a new rotating assembly... Probably the one of the scat options...

Yep, I use Excel :)
 
Indycars said:
I suspect Australia uses the RON rating and the US uses R+M/2 rating, which is lower that RON. Maybe Grumpy will have an idea how the two ratings compare.
Click to expand...

Yes, after a bit of research, it seems we use the RON rating.. Based on Wikipedia's say so, it looks like the 98 RON equivalent is 93-94 in R+M/2 rating...

What does that indicate for DCR limit for what I'm planning?
 
JimmyDuncan said:
What does that indicate for DCR limit for what I'm planning?
Click to expand...

Try to stay at or below 8.25. At 8.25 you are on the limit and may experience some detonation. Some of this depends on what you do to the combustion chambers. Polishing the chamber and the valves will help. Remove any spark plug threads that are showing with the spark plug in place. Sharp edges are your enemy.

This Excel spreadsheet will help you get your thoughts organized and help you decide exactly what modifications you will actually do and in what order. Don't hesitate to modify the Excel file to fit your project.

http://garage.grumpysperformance.com/index.php?threads/component-check-build-sequence-tracking.4894/

ComponentCheck&BuildSequencePartial.jpg
 
Indycars said:
Try to stay at or below 8.25. At 8.25 you are on the limit and may experience some detonation. Some of this depends on what you do to the combustion chambers. Polishing the chamber and the valves will help. Remove any spark plug threads that are showing with the spark plug in place. Sharp edges are your enemy.

This Excel spreadsheet will help you get your thoughts organized and help you decide exactly what modifications you will actually do and in what order. Don't hesitate to modify the Excel file to fit your project.

http://garage.grumpysperformance.com/index.php?threads/component-check-build-sequence-tracking.4894/

View attachment 5722
Click to expand...

Thanks. That helps.

I intend to do some port and polishing.. it sounds like it's very important to the performance and durability. It also looks satisfying :)

The build sequence spreadsheet will be a big help too. It's great.
 
I'm thinking I will use the build that David Vizard describes in his book as a basis for my build. pg 157 Engine #7 Entry level 383.

vizard 383.jpg

Quite a few of the components I had already put on my list before reading it. But, I hope to use alloy heads and the stroker rods he recommends. I think using hydraulic flat tappet over roller will make it affordable. It won't be a daily driver and will only be pushed hard occasionally.. I will need a new oil pan (the stock one is pretty bashed up..) so I'll upgrade there. Hopefully I can bring it in close to budget... What are everyone's thoughts on that as a plan?

Is there anything in that build that anyone would change to improve performance/stay on budget/improve durability?
 
the profiler or brodix aluminum heads would be far superior to the ported stock iron heads.
the 10:1 compression , scat rotating assembly is a good idea as is the edelbrock air gap intake , If personally suggest finding a 7-8 quart baffled oil pan that fits the cars chassis, a 650cfm- 750 cfm vacuum secondary carb
due to the cars weight and gearing ID suggest a cam more like this, as a good performance choice and about 9.7:1 compression
http://www.cranecams.com/product/cart.php?m=product_detail&p=23967
with a 3.73:1 rear gear and a 700r4 over drive transmission with a 3000 rpm stall converter
384fg1.png

or you could maximize the peak power if you boost the compression a bit to about 10.3:1 and use a cam like this with the same stall speed and rear gearing.
but at the cost of a slightly lower off idle torque and a rougher idle, keep in mind that youll be using that off idle to about 4500rpm power band about 90% of the time while driving on the street and rarely use that 4500rpm-6300 power band so yes it might not seem important but in real use it will be!
http://www.cranecams.com/product/cart.php?m=product_detail&p=24424
383fg2.png
 
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That cam sure looks like a solid lifter and not a hydraulic with .022 inches of lifter clearance.


CraneCams99893.JPG
 
Use The Crane Cam posted last.
He has chose a Flat Tappet Solid.
Crane is BETTER THAN COMP.

Its A Thumper with fair driving characteristics.
 
It takes 10-15 degrees more Advertised Duration or At .050" lift of Hydraulic cams Vs Solid lifter cams.

More Performance with Less.
Solid profile cams ARE MORE RELIABLE IN PERFORMANCE USE.
 
grumpyvette said:
the profiler or brodix aluminum heads would be far superior to the ported stock iron heads.
the 10:1 compression , scat rotating assembly is a good idea as is the edelbrock air gap intake , If personally suggest finding a 7-8 quart baffled oil pan that fits the cars chassis, a 650cfm- 750 cfm vacuum secondary carb
due to the cars weight and gearing ID suggest a cam more like this, as a good performance choice and about 9.7:1 compression
http://www.cranecams.com/product/cart.php?m=product_detail&p=23967
with a 3.73:1 rear gear and a 700r4 over drive transmission with a 3000 rpm stall converter
384fg1.png

or you could maximize the peak power if you boost the compression a bit to about 10.3:1 and use a cam like this with the same stall speed and rear gearing.
but at the cost of a slightly lower off idle torque and a rougher idle.
keep in mind that youll be using that off idle to about 4500rpm power band about 90% of the time while driving on the street and rarely use that 4500rpm-6300 power band so yes it might not seem important but in real use it will be!
http://www.cranecams.com/product/cart.php?m=product_detail&p=24424
383fg2.png
Click to expand...

Thanks Grumpy :)

The plan is coming together...

It'll be good to have a shopping list and a ball park idea on what it will all cost... :rolleyes:

Can you explain the reason you recommend that cam over the COMP cam Vizard suggests? You mention weight and gearing..?

At this stage a TH350 will go in and I'll keep an eye out for a TH700 down the track.. Forums I read don't seem to think they are much good though...? Initially I'll be cruising about on a less than ideal rear end also, but, I'll work towards the end goal as you suggest :)

One question re: trans, gearing and stall convertor combo... In my state in Australia, the speed limit on most highways is 100kmph (60 mph), so doing the math with 3.73 gears, 1:1 cruising gear and my current 24" tires, I get a cruise rpm of 3133. Is 133 enough above the 3000 stall to function properly? Also, if I put larger wheels and tires on later, am I going to have problems?

Thanks again.
 
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You can build a 383 as Grumpy says for about the same amount of money. With the added cubic inches and longer stroke you'll have more available torque.
 
I also think a bigger oil pan is a good idea. (probably a high volume pump too + hd pump shaft and a windage screen)
If you get a quality torque converter(stall at 3000 rpm).. the car should be rolling/cruising under 3000 rpm.
I try not to go over 470-475 lift with stock head(if that's what your using). any more and you may get clearance issue.(i think we need the Crane cam posted above but hydraulic version)
here's the link for the David Vizard Comp cam spec:
http://www.compcams.com/v002/Pages/395/XR270HR-10.aspx

The Crane cam's a better fit
http://www.cranecams.com/product/cart.php?m=product_detail&p=23967

Or this cam:
http://www.summitracing.com/int/parts/cca-12-322-4/overview/make/chevrolet
 
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